Many of the children in my building leave their bikes in the stairwell. I understand their reason for doing so: the lack of room in their apartment for bikes. However, it makes it difficult for me to walk the stairs. One day I got annoyed and put one of the bikes outside the building. The father of the boy who owned the bike saw what I did and didn’t say anything. However, the next morning the bike was gone and then I heard from him. He said I have to pay him for the bike since I placed it in an unsafe place, whereas in the stairwell bikes were never stolen. Is he correct?
There are two issues: One is if one is liable for damage resulting from moving someone else’s object from a safe place to an unsafe place. The second is whether, if the person is liable, the fact that the owner saw what was transpiring frees him from this liability.
The issue of moving another person’s object from a safe place to an unsafe place is discussed in various places in Choshen Mishpot. An extreme example is when a person placed objects on someone else’s property without permission and the property owner wants to move the objects off of his property. The Ramo (319, 1), whose opinion is authoritative for Ashkenazim, follows the opinion of the Rosh that the property owner must inform the owner of the object before he moves the object to a public place. If the property owner removed the object without informing the owner, he is liable for damages to the object. Therefore, in your situation where it is customary to keep bikes in the stairwell and therefore permitted, you are certainly liable.
Rav Moshe Feinstein (Choshen Mishpot 2, 56) was asked about a manufacturer of esrog cartons who failed to remove the cartons after the two months he had permission to store them by someone. Rav Moshe ruled that even after two years the property owner would be liable for any damage if he placed the cartons in an unsafe place. He further ruled that even the Rambam and Mechabeir, who disagree with the Rosh and Ramo, agree that if the owner of the object is not in town one may not move the object to an unsafe place. The Pischei Teshuvo (319, 1) cites a Chavos Ya’ir who made a property owner pay for moving such objects into a place where some were stolen and some were rained upon.
There is a dispute among the poskim why the property owner is liable. The Nesivos (25, 1: 291, 2) maintains that moving an object from a safe place to an unsafe place is an act of damage and thus he is considered to have directly caused any subsequent damage. However, others (e.g. the above cited Chavos Ya’ir, the Avnei Choshen (siman 291)) maintain that one is not considered as having damaged the object by placing it in an unsafe place, but rather he is liable if the object was stolen or damaged because he caused the damage and this type of causative damage is classified as garmi.
Having established that one who moves bikes to an unsafe place is liable for any eventual damage, we must address the second question: Whether the fact that the owner of the bikes saw their removal is halachically significant.
The Gemoro (Bava Kama 93A) rules that one who is told by the owner of an object that he may damage his object is not liable if he did just that. There is a dispute why he is absolved of liability. Tosafos understands that the reason is because by his saying to someone that he may damage his object the owner waived his right to collect damages. The Ketsos (246, 1) however, disagrees, and says the reason is because one who damages with permission is considered as if he did not damage someone else’s object.
In your situation you were not explicitly told that you may damage the bike. It was just that the owner was quiet when he saw you moving his bike. The Gemoro (Bava Kama 27A) discusses a person who was present when someone placed a hot coal on his garment. The Gemoro proves that the one who placed the coal is liable even though the garment’s owner was present and remained silent. The Rashbo (Commentary to Bava Kamo 93A) explains the difference between the two Gemoros is that it is critical for one to be told explicitly that he may damage the object and it does not suffice if the owner was only quiet when he saw his property being damaged. Since one can give other reasons for the owner’s passivity, we cannot conclude that he meant to waive his right to collect damages merely because he saw his object being damaged.
Your case is not precisely the case of the Gemara because in the case of the Gemara the owner of the object saw his object being damaged, whereas in your situation the owner only saw his object being placed in a precarious position. However, this difference is not halachically significant. Proof for this can be derived from the Commentary of the Rashbo’s disciple (Bava Metsiyo 83A) who rules that a porter is liable if he moved by himself an object which is normally transported by two people even though the owner saw the porter pick up the object by himself.
In conclusion, the owner is correct. You are liable for the stolen bike.